view.php

<?php defined( 'ABSPATH' ) || exit;

class TDB_View {

  /**
   * @var string View name
   */
  protected $name = '';

  /**
   * @var array View args
   */
  public $args = array();

  /**
   * TDB_View constructor.
   *
   * @since 1.0.0
   *
   * @param string    $name
   * @param array     $args
   */
  public function __construct( $name, $args ) {

      $this->name = $name;

      $this->args = wp_parse_args( $args, array(
          'menu_title' => ucfirst( $this->name ),
          'page_title' => ucfirst( $this->name ),
          'menu_slug' => $this->name,
          'parent_slug' => '',
          'show_in_menu' => true,
          'menu_icon' => '',
          'menu_position' => null,
          'capability' => 'manage_options',
      ) );

      $this->add_hooks();

  }

  /**
   * View hooks (called on constructor).
   *
   * @since 1.0.0
   */
  public function add_hooks() {

    add_action( 'admin_init', array( $this, 'admin_init' ) );

    // Note: sub-menus need to be registered after parent
    add_action( 'admin_menu', array( $this, 'admin_menu' ), empty( $this->args['parent_slug'] ) ? 10 : 11 );

    add_filter( 'parent_file', array( $this, 'parent_file' ), 10 );

    add_filter( 'submenu_file', array( $this, 'submenu_file' ), 10, 2 );

    add_action( 'adminmenu', array( $this, 'restore_plugin_page' ), 10, 2 );

    add_filter( 'screen_options_show_screen', array( $this, 'show_screen_options' ), 10, 2 );

    add_filter( 'screen_settings', array( $this, 'maybe_screen_settings' ), 10, 2 );

    add_filter( 'admin_init', array( $this, 'maybe_set_screen_settings' ), 11 );
    add_filter( 'tdb-set-screen-option', array( $this, 'set_screen_settings' ), 10, 3 );
  }

  public function show_screen_options( $show_screen, $screen ) {

      if( ! $this->is_current_view() ) {
          return $show_screen;
      }

      $screen_slug = explode( '_page_', $screen->id );

      if( isset( $screen_slug[1] ) &&  $screen_slug[1] === $this->args['menu_slug'] ) {
          return true;
      }

      return $show_screen;

  }

  /**
   * Check if current screen is own.
   *
   * @since 1.0.0
   *
   * @param string    $screen_settings    Screen settings.
   * @param WP_Screen $screen             WP_Screen object.
   *
   * @return string   $screen_settings
   */
  public function maybe_screen_settings( $screen_settings, $screen ) {

      if( ! $this->is_current_view() ) {
          return $screen_settings;
      }

      $screen_slug = explode( '_page_', $screen->id );

      // Check if current screen matches this menu slug
      if( isset( $screen_slug[1] ) &&  $screen_slug[1] === $this->args['menu_slug'] ) {

          global $tdb_registered_tables, $tdb_table;

          if( ! isset( $tdb_registered_tables[$this->name] ) ) {
              return $screen_settings;
          }

          // Set up global vars
          $tdb_table = $tdb_registered_tables[$this->name];

          ob_start();
          $this->screen_settings( $screen_settings, $screen );
          $screen_settings .= ob_get_clean();

      }

      return $screen_settings;

  }

  /**
   * Screen settings text displayed in the Screen Options tab.
   *
   * @since 1.0.0
   *
   * @param string    $screen_settings    Screen settings.
   * @param WP_Screen $screen             WP_Screen object.
   */
  public function screen_settings( $screen_settings, $screen ) {
      // Override
  }

  /**
   * Saves view options.
   *
   * Function based on set_screen_options()
   *
   * @since 1.0.0
   *
   * @see set_screen_options()
   */
  function maybe_set_screen_settings() {

      if( ! $this->is_current_view() ) {
          return;
      }

      if ( isset( $_POST['wp_screen_options'] ) && is_array( $_POST['wp_screen_options'] ) ) {
          check_admin_referer( 'screen-options-nonce', 'screenoptionnonce' );

          if ( ! $user = wp_get_current_user() ) {
              return;
          }

          $option = $_POST['wp_screen_options']['option'];
          $value = $_POST['wp_screen_options']['value'];

          if ( $option != sanitize_key( $option ) ) {
              return;
          }

          $option = str_replace('-', '_', $option);

          /**
           * Filters a screen option value before it is set.
           *
           * The filter can also be used to modify non-standard [items]_per_page
           * settings. See the parent function for a full list of standard options.
           *
           * Returning false to the filter will skip saving the current option.
           *
           * @since 1.0.0
           *
           * @see set_screen_options()
           *
           * @param bool|int $value  Screen option value. Default false to skip.
           * @param string   $option The option name.
           * @param int      $value  The number of rows to use.
           */
          $value = apply_filters( 'tdb-set-screen-option', false, $option, $value );

          if ( false === $value )
              return;

          update_user_meta( $user->ID, $option, $value );

          $url = remove_query_arg( array( 'pagenum', 'apage', 'paged' ), wp_get_referer() );
          if ( isset( $_POST['mode'] ) ) {
              $url = add_query_arg( array( 'mode' => $_POST['mode'] ), $url );
          }

          wp_safe_redirect( $url );
          exit;
      }
  }

  /**
   * Screen option value before it is set.
   *
   * The filter can also be used to modify non-standard [items]_per_page
   * settings. See the parent function for a full list of standard options.
   *
   * Returning false to the filter will skip saving the current option.
   *
   * @since 1.0.0
   *
   * @see set_screen_options()
   *
   * @param bool|int $value_to_set    Screen option value to set. Default false to skip.
   * @param string   $option          The option name.
   * @param int      $value           The option value.
   *
   * @return bool|mixed               False to skip or any other value to set as option value
   */
  public function set_screen_settings( $value_to_set, $option, $value ) {

      // Override

      return $value_to_set;

  }

  /**
   * Create a new menu
   *
   * @since 1.0.0
   */
  public function admin_menu() {

    // Override capability by the table capability
    $tdb_table = tdb_get_table_object( $this->name );

    if( ! empty( $tdb_table->capability ) ) {
      $this->args['capability'] = $tdb_table->capability;
    }

    if( ! $this->args['show_in_menu'] ) {

      add_submenu_page( '', $this->args['page_title'], $this->args['menu_title'], $this->args['capability'], $this->args['menu_slug'], array( $this, 'render' ) );

    } else {

      if( empty( $this->args['parent_slug'] ) ) {

        // Top menu
        add_menu_page( $this->args['page_title'], $this->args['menu_title'], $this->args['capability'], $this->args['menu_slug'], array( $this, 'render' ), $this->args['menu_icon'], $this->args['menu_position'] );

      } else {

        // Sub menu
        add_submenu_page( $this->args['parent_slug'], $this->args['page_title'], $this->args['menu_title'], $this->args['capability'], $this->args['menu_slug'], array( $this, 'render' ) );
      }
    }
  }

  /**
   * Parent file fix when a view is registered in a submenu
   *
   * @since 1.0.0
   */
  public function parent_file( $parent_file ) {

      global $tdb_table, $plugin_page;

      if( ! $this->is_current_view() ) {
          return $parent_file;
      }

      $list_view_args = $tdb_table->views->list->args;

      // If not empty parent slug, override actual parent slug
      if( ! empty( $this->args['parent_slug'] ) ) {
          $parent_file = $this->args['parent_slug'];

          if( $this->args['menu_slug'] !== $list_view_args['menu_slug'] ) {
              // Hack required to make parent file work because get overwritten on get_admin_page_parent() function
              $plugin_page = null;
          }
      }

      // If we are on an add or edit view and list is displayed on menu, apply the list parent slug
      if( $this->args['menu_slug'] !== $list_view_args['menu_slug'] ) {

          if( $list_view_args['show_in_menu'] && ! empty( $list_view_args['parent_slug'] ) ) {
              $parent_file = $list_view_args['parent_slug'];

              // Hack required to make parent file work because get overwritten on get_admin_page_parent() function
              $plugin_page = null;
          }

      }

      return $parent_file;

  }

  /**
   * Submenu file fix when a view is registered in a submenu
   *
   * @since 1.0.0
   */
  public function submenu_file( $submenu_file, $parent_file ) {

      global $tdb_table;

      if( ! $this->is_current_view() ) {
          return $submenu_file;
      }

      $list_view_args = $tdb_table->views->list->args;

      // If we are on an add or edit view and list is displayed on menu, then highlight list view
      if( $this->args['menu_slug'] !== $list_view_args['menu_slug'] ) {
          if( $list_view_args['show_in_menu'] && ! empty( $list_view_args['parent_slug'] ) ) {
              $submenu_file = $list_view_args['menu_slug'];
          }
      }

      return $submenu_file;

  }

  /**
   * Restore global $plugin_page since it was required to get overwritten on parent_file()
   *
   * @since 1.0.0
   */
  public function restore_plugin_page() {

      global $tdb_table, $plugin_page;

      if( ! $this->is_current_view() ) {
          return;
      }

      $list_view_args = $tdb_table->views->list->args;

      // If we are on an add or edit view and list is displayed on menu, restore plugin page too
      if( $this->args['menu_slug'] !== $list_view_args['menu_slug'] ) {

          // If not empty parent slug then restore plugin page
          if( ! empty( $this->args['parent_slug'] ) ) {
              $plugin_page = $this->args['menu_slug'];
          }

          if( $list_view_args['show_in_menu'] && ! empty( $list_view_args['parent_slug'] ) ) {
              $plugin_page = $this->args['menu_slug'];
          }
      }

  }

  public function is_current_view() {

      global $tdb_registered_tables, $pagenow;

      if( $pagenow !== 'admin.php' ) {
          return false;
      }

      if( ! isset( $_GET['page'] ) ) {
          return false;
      }

      if( empty( $_GET['page'] ) || $_GET['page'] !== $this->args['menu_slug'] ) {
          return false;
      }

      if( ! isset( $tdb_registered_tables[$this->name] ) ) {
          return false;
      }

      return true;
  }

  public function get_slug() {
      return $this->args['menu_slug'];
  }

  public function get_link() {
      return admin_url( "admin.php?page=" . $this->args['menu_slug'] );
  }

  /**
   * View admin init.
   *
   * This function is called on admin_init hook.
   * Includes some checks to determine if the init() function should be called.
   *
   * @since 1.0.0
   */
  public function admin_init() {

    global $tdb_registered_tables, $tdb_table;

    if( ! $this->is_current_view() ) {
      return;
    }

    // Setup the global TDB_Table object for this screen
    $tdb_table = $tdb_registered_tables[$this->name];

    // Run the init function
    $this->init();
  }

  /**
   * View init.
   *
   * Run redirects here to avoid "headers already sent" error.
   *
   * @since 1.0.0
   */
  public function init() {
    do_action( "tdb_init_{$this->name}_view", $this );
  }

  /**
   * View content.
   *
   * @since 1.0.0
   */
  public function render() {
    do_action( "tdb_render_{$this->name}_view", $this );
  }
}